Ordered manifold plenum for 1997 Lesabre

John Canon

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1997 Lesabre Limited Gran Touring Suspension
Now it's my turn. I ordered the ATP 106001 plenum and the Fel-Pro metal lower gasket set from RockAuto, and the Dorman 47065HP elbows locally. I have rebuilt engines before, so this should be straightforward. When the job is done, I will talk about the initial symptoms and diagnosis.

Question: where can I get the new and improved O-rings for the elbows?
Also: is there a part number for the Permatex thread locker?
 
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HotZ28

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Question: where can I get the new and improved O-rings for the elbows?
Also: is there a part number for the Permatex thread locker?
I installed the Dorman aluminum elbows about 10-yrs ago with the original O-rings & no leaks yet! Of course I cleaned the female inlet with a little piece of scotch bright and applied some silicone to both surfaces. Do not use "thread locker", instead use Permatex’s Thread Sealant with PTFE. You can buy small quantities @ most auto part stores. Do not forget to clean the bolt threads & use brake clean on the threads, male & female.
1669182506513.png
 

John Canon

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I will follow your O-ring procedure. They say to use threadlocker on the lower manifold bolts. I guess medium strength is fine.

I have some good teflon thread seal paste, but I am not sure where you want me to use it. On other engines I would use it where a bolt extended into the water jacket.

Tonight I started the dismantle ... quite easy and straightforward. The tricky problem is the big wire harnesses are quite stiff. Enjoyable work so far.
 

HotZ28

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I will follow your O-ring procedure. They say to use threadlocker on the lower manifold bolts. I guess medium strength is fine.

I have some good teflon thread seal paste, but I am not sure where you want me to use it. On other engines I would use it where a bolt extended into the water jacket.

Tonight I started the dismantle ... quite easy and straightforward. The tricky problem is the big wire harnesses are quite stiff. Enjoyable work so far.
Who is "they" that says to use thread locker on the LIM bolts? After the engine goes through several heat cycles, the bolts need to be re-torqued to specification, due to heat & expansion. Thread lock will not allow that to happen without breaking the seal, or bolt. Use the PTFE seal on the bolts!
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BuickGirlFromMars

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Who is "they" that says to use thread locker on the LIM bolts? After the engine goes through several heat cycles, the bolts need to be re-torqued to specification, due to heat & expansion. Thread lock will not allow that to happen without breaking the seal, or bolt. Use the PTFE seal on the bolts!
plus those small diameter bolts , if you use too much blue, will lock in harder than the force needed to shear the heads.
 
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BuickGirlFromMars

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1999 Buick Park Avenue Ultra (Supercharged) , 1977 Buick Electra Limited (350 SBB)
I will follow your O-ring procedure. They say to use threadlocker on the lower manifold bolts. I guess medium strength is fine.

I have some good teflon thread seal paste, but I am not sure where you want me to use it. On other engines I would use it where a bolt extended into the water jacket.

Tonight I started the dismantle ... quite easy and straightforward. The tricky problem is the big wire harnesses are quite stiff. Enjoyable work so far.
unclip the ignition subharness, and pull up any tie downs along by the egr, around the TB, and all the sensors. as a assembly, fold it over
 

2007LucerneCXL

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O-rings Smaller: 25537068 x3, Larger: 24502846 x1 Available Rockauto.com, Amazon etc search by the GM part number on Google and you will find sources.
 

John Canon

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1997 Lesabre Limited Gran Touring Suspension
Who is "they" that says to use thread locker on the LIM bolts? After the engine goes through several heat cycles, the bolts need to be re-torqued to specification, due to heat & expansion. Thread lock will not allow that to happen without breaking the seal, or bolt. Use the PTFE seal on the bolts!
"They" is the 1997 Lesabre FSM on page 6A-40
Buick LIM FSM.jpg
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2007LucerneCXL

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There are different types and levels of locking compounds, it's not one size fits all, so confusion can come when a word is used and not the actual product specifications. Yes there are some that once set will never come apart and others that will make the connection snug but removable. See the link below.

 

2007LucerneCXL

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It's all in the details, lol.
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2007LucerneCXL

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I would talk to engineers and they would say "kinda" and I would respond "Oh is like kinda being pregnant", details LMAO.
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lbear

2004 Buick LeSabre Limited Celebration
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I will follow your O-ring procedure. They say to use threadlocker on the lower manifold bolts. I guess medium strength is fine.

I have some good teflon thread seal paste, but I am not sure where you want me to use it. On other engines I would use it where a bolt extended into the water jacket.

Tonight I started the dismantle ... quite easy and straightforward. The tricky problem is the big wire harnesses are quite stiff. Enjoyable work so far.

USE BLUE THREAD LOCKER. I didn't use it and only applied thread sealant on the bolts and they loosened up after a few hundred miles and my intake manifold end seals began leaking oil. I had to redo the entire lower intake job again. The bolts were all loose when I redid the intake manifold job. I torqued them and used thread sealant the first time but thread sealant is not designed to prevent loosening of the bolt. Thread sealant is designed to "seal" the bolt to prevent fluids from leaking past them.

This time I used blue thread locker like GM states in the repair manual. Without it, the bolts will work themselves loose and you will most likely have the lower intake leak. The second time around after using blue thread locker, I marked some of the bolts and none of them have loosened since and I don't have any leaks on the intake manifold.
 
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lbear

2004 Buick LeSabre Limited Celebration
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Question: where can I get the new and improved O-rings for the elbows?
Also: is there a part number for the Permatex thread locker?

Get the GM AC Delco o-rings and replace the Dorman supplied ones. The Dorman ones are okay but some have reported failures a few thousand miles later. Supposedly Dorman used lower quality o-rings that don't do well over time with DexCool.

3 of the o-rings are the same size and 1 o-ring is a little bit larger.
 

John Canon

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1997 Lesabre Limited Gran Touring Suspension
On my list.

I had a similar situation with my road bike (bicycle.) I took the rear wheel apart to straighten the rim and install all new spokes. I made a drawing of the criss-cross pattern before disassembly. While tightening the new spokes, I added a drop of oil to each thread, for some reason.

The wheel would not hold true while riding, so I tried adjusting the spoke tensions. It was hopeless. So I added a tiny drop of Permatex 294 green threadlocker to each thread and the wheel held true after that.

Permatex 294 is excellent for most small service work because it is "wicking." You can apply is to assembled fittings. It is gold!
 

HotZ28

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Once the LIM bolts are torqued to specification they will not loosen. As mentioned earlier, the gaskets shrink due to heat & contraction. That makes it appear that the bolts have loosened, but that is not the case.
 
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